US2648793A

US2648793A - Thermionic tube and plate assembly for such tubes

Info

Publication number: US2648793A
Application number: US160461A
Authority: US
Inventors: Wihtol Weltis
Original assignee: ROBERT DOLLAR Co
Current assignee: ROBERT DOLLAR Co
Priority date: 1950-05-06
Filing date: 1950-05-06
Publication date: 1953-08-11
Anticipated expiration: 1970-08-11

Description

Aug. 11, 1953 w. WlHTOL v 2,643,793

THERMIONIC TUBE AND PLATE ASSEMBLY FOR SUCH TUBES Filed May 6, 1950 INVENTOR. 14/51. 278 W/HTOL I HIS .A TT'ORNE vs Patented Aug. 11, 1953 THERMIONIO TUBE AND PLATE ASSEMBLY FOR- SUCH TUBES Weltis Wihtol, Redwood City, Calif., assignor to The Robert Dollar Company, Redwood City,

Calif., a corporation Application May 6, 1950, Serial No. 160,461

8 Claims.

This invention relates to thermionic tubes or like devices and to improved plate assemblies for such tubes.

The principal object of the invention is'to provide an improved thermionic tube and plate assembly therefore permitting a vastly greater rate of heat dissipation than that found in any comparable prior art plate assembly.

A further object of the invention is to provide a thermionic tube in which the improved plate assembly and the glass envelope are so related that they cooperate to increase the rate of heat dissipation appreciably over that or prior art thermionic tubes.

Other objects, advantages, and inherent functions of the invention will become apparent as the invention is more fully understood from the following description, which, taken in connection with the accompanying drawings, disclose a pre-' ferred embodiment of the invention.

The accompanying drawings illustrate a preferred embodiment of the invention in which Figure l is an elevational view of the preferred embodiment of the invention;

Figure 2 is an enlarged elevational view of the plate assembly illustrated in Figure 1; and

Figure 3 is a top plan view of the plate assembly illustrated in Figure 2.

The drawings of the preferred embodiment show a conventional general purpose radiation cooled triode or three element thermionic tube. In accordance with usual practice, the triode is provided with a base I which is secured to a glass envelope 2. There is mounted within the glass envelope 2 a filament or cathode 3. Filament leads 4 connect opposite ends of the filament to filament terminals 5, the filament terminals 5 being located at the bottom of the base I. A grid 6 surrounds the filament 3 and is connected through a grid lead I to a grid terminal 8 mounted in the side wall of the glass envelope 2. A plate or anode 9 surrounds the grid 6 and is connected through a plate or anode lead ill to a plate or anode terminal ll located at the top of the glass envelope 2.

The structure and operation of triode thermionic tubes of the type generally described above are well known to and understood by mechanics skilled in the art and provide a suitable environment for the invention hereinafter described. It is also well known to skilled mechanics that all of the power fed to the plate of a thermionic tube is not converted into usable power. Part of it is wasted in heat within the tube. In thermionic tubes there is a limit to the amount of power that a tube can dissipate in the form of heat without danger of damage to the tube. lhe amount of this power is known to mechanics skilled in the art as the maximum rated plate dissipation of the tube. In the past,

the prior art has suggested many expedients intended to increase the maximum plate dissipation of thermionic tubes. These expedients include a multitude of endeavors. For example, some prior art tubes have used finned plates or anodes, .and other prior art tubes have used plates or anodes coated with various kinds of materials. None has been wholly satisfactory.

This invention relates to a new and improved means of increasing the maximum plate dissipation of thermionic tubes and does it in a more efficient way than known prior art expedients. More specifically, the present invention comprehends a plate or anode assembly which includes an inner cylinder I2, the inner surface of which acts as the anode surface. An outer cylinder l3 surrounds the inner cylinder l2 and is 'arranged in coaxial alignment with the inner cylinder. The lower edges of the two cylinders are secured by means of a roll weld I4, and the upper ends of the two cylinders are secured by means of an open lattice-like web support 15. The web support It may be secured to the inner cylinder 12 and the outer cylinder I 3, for example, by means of spot welding. The upper end of the inner cylinder I2 is closed by means of a dome shaped cover Hi.

The dimensions and materials of the plate assembly are not critical and may vary widely without affecting the desired results. For example only, it has been found that a very satisfactory plate structure for a tube having a height of 12% inches and a normal plate dissipation of 450 watts, is obtained by forming the plate assembly with the inner diameter a. of the inner cylinder I2 of 1.500 inches, an outer diameter b of the inner cylinder [2 of 1.531 inches, an overall height 0 of the two cylinders of 2.125 inches, a height 11 of the dome l-6 of .500 inch, an outer diameter e of the outer cylinder l3 of 1.875 inches, and a height f of the lattice-like web support [5 of .187 inch. For example only, it has also been found that satisfactory metal for the plate assembly is tantalum. A number of other metals may be used, such as for example only molybdenum, tungsten and other pure metals or alloys.

In conjunction with this plate assembly it has also been found useful to construct the glass envelope 2 of glass which will transmit in the neighborhood of of infra-red rays having a wave length shorter than 2.6 microns and to operate the plate at such temperatures, say in the neighborhood of 1037 centigrade, that the peak wave length of the waves produced by said plate structure is shortened to 2.2 microns. Suitable glass having the foregoing properties is well known to mechanics skilled in the glass art and need not be described herein. Moreover, skilled mechanics in the thermionic tube art are able to select the proper voltage and current requirements to arrive at the suggested plate temperature, hence no details of voltage and current requirements are given.

It has been found by actual tests that thermionic tubes using the plate construction of this invention have a plate dissipation more than double that of otherwise identical tubes using the prior art finned plate construction and that such tubes have an increased useful life over such prior art tubes.

Although the plate assembly'is illustrated in association with a triode type thermionic tube and although specific dimensions and materials are stated, it will be understood that the invention has like utility in association with thermionic tubes having more or less than three elements and that difierent dimensions and materials may be used. It will be understood further that other embodiments of this invention may exist and that changes within the ambit of the claims may be made Without departing from the scope of this invention.

What is claimed is:

1. In a thermionic tube, a plat assembly having a metallic inner tubular anode, a metallic outer tube spaced from and surounding said anode, a continuous metallic joint connecting one end of said anode to the coresponding end of said outer tube, and a metallic lattice-like web support connecting the other end of said anode to the corresponding end of said outer tube, the space between said anode and outer tube being filled only with the atmosphere of said thermionic tube.

2. In a thermionic tube, a plate assembly having a metallic inner tubular anode, a metallic outer tube spaced from and surrounding said anode, a metallic lattice-like web support securing one end of the said anode to the corresponding end of said outer tube, and a dome like cover closing the end of said anode adjacent the end whereon there is secured said lattice-like web support, the space between said anode and outer tube being filled only with the atmosphere of said thermionic tube.

3. In a thermionic tube, a glass envelope adapt ed to transmit in the neighborhood of 90% of infra-red rays having a wave length shorter than 2.6 microns, and a plate assembly normally operable at a temperature whereat the peak length of the waves produced by said plate assembly is in the neighborhood of 2.2 microns, said plate assembly having a metallic inner tubular anode, a metallic outer tube spaced from and surrounding said anode, and a continuous metallic joint connecting one end of said anode to the corresponding end of said outer tube, the space between said anod and outer tube being filled only with the atmosphere of the tube.

4. In a thermionic tube, a glass envelope adapted to transmit in the neighborhood of 90% of infra-red rays having a wave length shorter than 2.6 microns, and a plate assembly normally operable at a temperature whereat the peak length of the waves produced by said plate assembly is in the neighborhood of 2.2 microns, said plate assembly having a metallic inner tubular anode, a metallic outer tube spaced from and surrounding said anode, a continuous metallic joint connecting one end of said anode to the corresponding end of said outer tube, and a metallic lattice-like web support connecting the other end of said anode to the corresponding end of said outer tube, the space between said anode and 4 outer tube being filled only with the atmosphere of said thermionic tube.

5. In a thermionic tube, a glass envelope adapted to transmit in the neighborhood of of infra-red rays having a wave length shorter than i 2.6 microns, and a plate assembly normally operable at a temperature whereat. the peak length of the waves produced by said plate assembly is in the neighborhood of 2.2 microns, said plate assembly having a metallic inner tubular anode, a metallic outer tube spaced from and surrounding said anode, a metallic lattice-like web support securing one end of the said anode to the corresponding end of said outer tube, and a dome like cover closing the end of said anode adjacent the end whereon there is secured said lattice-like web support, the space between said anode and outer tube being filled only with the atmosphere of said thermionic tube.

6. In a thermionic tube, a'plate assembly and a glass envelope adapted to transmit in the neighborhood of 90% of the infra-red rays produced by said plate assembly, said plate assembly normally operable at a temperature whereat the peak length of the waves produced by said plate assembly is in the neighborhood of 2.2 microns, said plate assembly having a metallic inner tubular anode, a metallic outer tube spaced from and surrounding said anode, and a continuous metallic joint connecting one end of said anode to the corresponding end of said outer tube, the space between said anode and outer tube being filled only with the atmosphere of the tube.

7. In a thermionic tube, a plate assembly and a glass envelope adapted to transmit in the neighborhood of 90% of the infra-red rays produced by said plate assembly, said plate assembly having a metallic inner tubular anode, a metallic outer tube spaced from and surrounding said anode, a continuous metallic joint connecting one end of said anode to the corresponding end of said outer tube, and a metallic lattice-like web support connecting the other end of said anode to the corresponding end of said outer tube, the space between said anode and outer tube being filled only with theatmosphere of said thermionic tube.

8. In a thermionic tube, a plate assembly and a glass envelope adapted to transmit in the neighborhood of 90% of the infra-red rays produced by said plate assembly, said plate assembly having a metallic inner tubular anode, a metallic outer tube spaced from and surrounding said anode, a metallic lattice-like web support securing one end of the said anode to the corresponding end of said outer tube, and a dome like cover closing the end of said anode adjacent the end whereon there is secured said lattice-like web support, the space between said anode and outer tube being filled only with the atmosphere of said thermionic tube.

WELTIS WIHTOL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,962,218 Snow June 12, 1934 1,988,398 Saxl Jan. 15, 1935 2,407,857 Verhoeff Sept. 17, 1946 2,423,815 Ramsay July 8, 1947 2,466,430 Hutchison Apr. 5, 1949 2,466,967 Pressel et al. Apr. 12, 1949 FOREIGN PATENTS Number Country Date 142,582 Switzerland Dec. 1, 1930